In general, a knee airbag module for a vehicle includes a knee airbag, which is installed at a lower portion inside an instrument panel to receive a steering wheel, received in a folded state, and deployed toward the knee of an occupant upon vehicle collision, and an inflator which supplies high-pressure gas to the knee airbag.
If impact is detected by a sensor upon vehicle collision, the inflator operates to supply high-pressure gas to the knee airbag. Since the knee airbag is deployed toward the knee of the occupant after being inflated in a predetermined volume due to high-pressure gas, the knee of the occupant is prevented from being damaged due to the collision with the instrument panel at the front thereof.